The paper treats the modeling and simulation of sheet metal hydroforming taking into account fluid pressure and fluid velocity effects. A hydro-mechanical model is proposed to determine the fluid flow and the pressure variation in the die cavity in case of sheet hydroforming. The hydrodynamical model for the fluid flow between the sheet and the blank holder is based on Reynold's equation. A numerical and experimental hydromechanical deep drawing of a cylindrical cup validates the predictions of the proposed approach.